fix(identity): align Group entity with IAuditableEntity and encapsulate soft-delete

- Implement IAuditableEntity on Group (CreatedOnUtc, LastModifiedOnUtc, LastModifiedBy)
- Map renamed properties to existing DB columns via HasColumnName (no migration needed)
- Encapsulate ISoftDeletable with private setters and Delete() domain method
- Upgrade GroupDto.CreatedAt from DateTime to DateTimeOffset (preserves JSON property name)
- Use TimeProvider.System for testable timestamps

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: iammukeshm

src/Modules/Identity/Modules.Identity.Contracts/DTOs/GroupDto.cs

@@ -10,5 +10,5 @@ public class GroupDto
     public int MemberCount { get; set; }
     public IReadOnlyCollection<string>? RoleIds { get; set; }
     public IReadOnlyCollection<string>? RoleNames { get; set; }
-    public DateTimeOffset CreatedOnUtc { get; set; }
+    public DateTimeOffset CreatedAt { get; set; }
 }

src/Modules/Identity/Modules.Identity/Domain/Group.cs

@@ -36,7 +36,7 @@ public static Group Create(string name, string? description = null, bool isDefau
             Description = description,
             IsDefault = isDefault,
             IsSystemGroup = isSystemGroup,
-            CreatedAt = TimeProvider.System.GetUtcNow().UtcDateTime,
+            CreatedOnUtc = TimeProvider.System.GetUtcNow(),
             CreatedBy = createdBy
         };
     }
@@ -45,14 +45,21 @@ public void Update(string name, string? description, string? modifiedBy = null)
     {
         Name = name;
         Description = description;
-        ModifiedAt = TimeProvider.System.GetUtcNow().UtcDateTime;
-        ModifiedBy = modifiedBy;
+        LastModifiedOnUtc = TimeProvider.System.GetUtcNow();
+        LastModifiedBy = modifiedBy;
     }
 
     public void SetAsDefault(bool isDefault, string? modifiedBy = null)
     {
         IsDefault = isDefault;
-        ModifiedAt = TimeProvider.System.GetUtcNow().UtcDateTime;
-        ModifiedBy = modifiedBy;
+        LastModifiedOnUtc = TimeProvider.System.GetUtcNow();
+        LastModifiedBy = modifiedBy;
+    }
+
+    public void Delete(string? deletedBy = null)
+    {
+        IsDeleted = true;
+        DeletedOnUtc = TimeProvider.System.GetUtcNow();
+        DeletedBy = deletedBy;
     }
 }

src/Modules/Identity/Modules.Identity/Features/v1/Groups/CreateGroup/CreateGroupCommandHandler.cs

@@ -43,7 +43,7 @@ public async ValueTask<GroupDto> Handle(CreateGroupCommand command, Cancellation
                 .ToListAsync(cancellationToken);
             resolvedRoles = rawRoles.Select(r => (r.Id, r.Name!)).ToList();
 
-            var invalidRoleIds = command.RoleIds.Except(resolvedRoles.Select(r => r.Item1)).ToList();
+            var invalidRoleIds = command.RoleIds.Except(resolvedRoles.Select(r => r.Id)).ToList();
             if (invalidRoleIds.Count > 0)
             {
                 throw new NotFoundException($"Roles not found: {string.Join(", ", invalidRoleIds)}");
@@ -74,9 +74,9 @@ public async ValueTask<GroupDto> Handle(CreateGroupCommand command, Cancellation
             IsDefault = group.IsDefault,
             IsSystemGroup = group.IsSystemGroup,
             MemberCount = 0,
-            RoleIds = resolvedRoles.Select(r => r.Item1).ToList().AsReadOnly(),
-            RoleNames = resolvedRoles.Select(r => r.Item2).ToList().AsReadOnly(),
-            CreatedOnUtc = group.CreatedOnUtc
+            RoleIds = resolvedRoles.Select(r => r.Id).ToList().AsReadOnly(),
+            RoleNames = resolvedRoles.Select(r => r.Name).ToList().AsReadOnly(),
+            CreatedAt = group.CreatedOnUtc
         };
     }
 }

src/Modules/Identity/Modules.Identity/Features/v1/Groups/GetGroupById/GetGroupByIdQueryHandler.cs

@@ -46,7 +46,7 @@ public async ValueTask<GroupDto> Handle(GetGroupByIdQuery query, CancellationTok
             MemberCount = memberCount,
             RoleIds = roleIds.AsReadOnly(),
             RoleNames = roleNames.AsReadOnly(),
-            CreatedAt = group.CreatedAt
+            CreatedAt = group.CreatedOnUtc
         };
     }
 }

src/Modules/Identity/Modules.Identity/Features/v1/Groups/GetGroups/GetGroupsQueryHandler.cs

@@ -67,7 +67,7 @@ public async ValueTask<IEnumerable<GroupDto>> Handle(GetGroupsQuery query, Cance
                 .Select(gr => roleNames.GetValueOrDefault(gr.RoleId, gr.RoleId))
                 .ToList()
                 .AsReadOnly(),
-            CreatedOnUtc = g.CreatedOnUtc
+            CreatedAt = g.CreatedOnUtc
         });
     }
 }

src/Modules/Identity/Modules.Identity/Features/v1/Groups/UpdateGroup/UpdateGroupCommandHandler.cs

@@ -117,7 +117,7 @@ private async Task<GroupDto> BuildResponseAsync(Group group, HashSet<string> rol
             MemberCount = memberCount,
             RoleIds = roleIds.ToList().AsReadOnly(),
             RoleNames = roleNames.AsReadOnly(),
-            CreatedOnUtc = group.CreatedOnUtc
+            CreatedAt = group.CreatedOnUtc
         };
     }
 }

src/Modules/Identity/Modules.Identity/Features/v1/Users/GetUserGroups/GetUserGroupsQueryHandler.cs

@@ -78,7 +78,7 @@ public async ValueTask<IEnumerable<GroupDto>> Handle(GetUserGroupsQuery query, C
                 .Select(gr => roleNames.GetValueOrDefault(gr.RoleId, gr.RoleId))
                 .ToList()
                 .AsReadOnly(),
-            CreatedOnUtc = g.CreatedOnUtc
+            CreatedAt = g.CreatedOnUtc
         });
     }
 }